Studies of the Interaction between Aβ Peptides and Carbon Nano-Materials

Abstract

The aggregation of amyloid-β peptides (Aβ) is considered as one of the mainly possible causes of the Alzheimer's diseases (AD). How to suppress the formation of toxic Aβ aggregates has been intensively concerned over the past several decades. Increasing evidence shows that whether carbon nano-materials could suppress or promote the aggregation depend on their physicochemical properties. However, as amyloid fibrillization is a complex process, their interaction dynamics remains elusive. In this presentation, we have investigated the interaction between Aβ(16-22) peptides/full-length Aβ peptides and three kinds of carbon nanomaterials (carbon nanotube, fullerene, and graphene) by utilizing atomic force microscopy (AFM), electrostatic force microscopy (EFM), Thioflavin T (ThT) fluorescence, combined with molecular dynamic (MD) simulations. Our experimental results demonstrate that all of the three carbon nano-materials could suppress the process of Aβ fibrillation. EFM and ThT fluorescence results further confirmed that the Aβ peptides are strongly absorbed on the surface of carbon nano-materials by forming non-fibrillar aggregates. At the molecular scale, it is found that carbon nano-materials dramatically inhibit the formation of ordered β-sheet-rich structures as the strong hydrophobic and aromatic stacking interactions between carbon nano-materials and Aβ peptides. In comparison, the fullerenes exhibit the most excellent inhibitory ability by the strong aromatic stacking of the fullerene hexagonal rings with the Phe rings, as well as the outstanding biocompatibility. Furthermore, we found that the bare carbon nanotube could dissociate the preformed fibrils to some extent. Our results provide novel clues for studying interaction in amyloid/carbon-material system and seeking amyloidosis inhibitors with carbon nanomaterials, which may have important potentials in the development of drug candidates against Alzheimer's disease.